The ExoMars mission is a two-part ESA-Roscosmos mission to Mars, with the Trace Gas Orbiter (TGO) reaching Martian orbit in late 2016 and the rover launching in 2020. The mission will study the Martian surface, investigating signs of past or present life, water and trace gases.
A landing site must be chosen for the rover and this work summarises the proposed sites, in particular investigating the distribution of (and risk posed by) Transverse Aeolian Ridges (TARs). These are features that are between ripples and dunes in size and morphology. The density of these features over each of the landing sites has been mapped, finding that Oxia Planum has a density of 4.9 ± 5.9 %, Aram Dorsum has a density of 2.72 ± 2.75 % and Mawrth Vallis has a density of 16.9 ± 7.9 %. Comparisons to Mars Science Laboratory's Curiosity rover have shown that the ExoMars rover is expected to sink 1.4 times further into equivalent ripples, and so it is necessary to investigate the rover response to TARs as their implications may be more severe.
In addition, this work examines a sedimentological deposit in the Oxia Planum landing site and finds that it is likely to be deltaic. This is one of twelve deltas that are proposed to have been created by the presence of multiple instance s of a northern ocean. Assuming an ocean shoreline would form an equipotential, it is proposed that an ocean was present in at least two distinct time periods, one in the late Noachian at an elevation of -2860 m (+/- 212 m) and one in the early Amazonian at an elevation of -2100 m (+/- 346 m). Recent studies have proposed the existence of an Amazonian active hydrological cycle, supporting the existence of the latter ocean, although having the largest ocean in the Amazonian era is unexpected.